Suspicious language
Highlights urgency, credential requests and common impersonation cues.
One free browser extension · Chrome · Edge · iPhone Safari
MailGuard. Know what is hiding in your inbox.
A free, privacy-first extension that checks opened Gmail, Outlook and Yahoo Mail messages, explains suspicious signals, and warns before you follow risky links — without uploading email content.
MailGuard v1.6.1 improves Yahoo Mail reader compatibility and adds in-extension connection diagnostics, alongside pre-click link warnings, scan-failure indicators and fraud checks. Download the free Chrome/Edge desktop preview below and allow access to Gmail, Outlook or Yahoo Mail. Live URL reputation and external AI analysis are not enabled. Safari iPhone still requires Apple's packaging and testing.
Chrome & Edge desktop preview · Unzip, open browser extensions, enable Developer mode, and choose Load unpacked. No automatic deletion or quarantine.
MailGuard
Example analysis · illustrative data
Example risk score
82/100
Reply-to does not match sender
Identity indicator
Message requests immediate sign-in
Social engineering
Link destination differs from displayed text
URL indicator
Scores are indicators, not proof. Results require human judgement; this is a fabricated example, not a real scan.
Automatic alerts and manual checks
Understand why an email deserves a second look.
MailGuard checks recognized opened Gmail, Outlook and Yahoo Mail messages, showing a compact scan status or a prominent phishing warning. If the message body cannot be read, it says so rather than showing a misleading clean result. Local pre-click warnings interrupt risky email links until the user decides whether to proceed. Website layouts vary, so real-account acceptance tests are still required.
Link inspection
Checks for misleading links, lookalike domains and risky URL patterns without opening them.
Sender & header clues
Flags sender/reply-to mismatches and relevant authentication headers when provided.
Email file analysis
Analyse pasted messages or exported .eml files and receive an explained risk assessment.
Optional enterprise roadmap
For organisations that need more.
01
Mailbox connections
Gmail and Microsoft 365 integration using scoped consent and secure server-side access.
02
Continuous scanning
Scheduled ingestion, alerting and repeatable risk reviews with clear failure reporting.
03
Controlled response
Administrator-approved quarantine, restore workflows and auditable actions.
04
Enterprise governance
Roles, retention policies, tenant isolation and measurable security operations reporting.
Security-first rollout
Mailbox integrations should use least-privilege OAuth scopes, encryption in transit and at rest, expiring secrets and audit logs. Live-domain reputation, authentication checks, tenant isolation and incident response workflows require end-to-end testing before production activation.
Who is MailGuard for?
Individuals
Check a suspicious message before opening links or sharing account details.
Businesses
Explore phishing analysis as an additional security layer for business email.
IT & security teams
Review explainable detection indicators and help employees make safer decisions.
Get the free MailGuard extension
Download MailGuard v1.6.1 free for Chrome and Edge desktop. Extract the ZIP, load the folder in your browser's extensions screen, and refresh your Gmail, Outlook or Yahoo Mail tab after installing. The Apple Safari release and browser-store listings are not yet available.